Wide-angle objective



DLMHUH nuul' 3,320,015 I I I May 16. 1967 L- BERTELE WIDE-ANGLE OBJECTIVE Filed larch 13. 1963 v Ludwig Belicia INVENTOR Dezsoe Steinncn ATTORNEY United States Patent 3,320,015 WIDE-ANGLE OBJECTIVE Ludwig Bertele, Heerbrugg, Switzerland, assignor of onehalf to Wild Heerbrugg Aktiengesellschaft, Heerbrugg, Switzerland Filed Mar. 13, 1963, Ser. No. 264,866 Claims priority, application Switzerland, Mar. 15, 1962, 3,137/ 62 3 Claims. (Cl. 350-216) The present invention relates to a wide-angle objective for picture-taking and for projection, in which the lens members are arranged in such manner that a collective lens member is embraced on one side by a diverging meniscus and on the other side by two diverging menisci with the formation of air spaces. The beforementioned three menisci have their concave surfaces turned to the collective inner member, in which the pupil, i.e. the narrowest constriction of rays, is located. If the diameter of the pupil has always the same size, a cut in the collective lens member is sufficient. If the diameter is variable, into the beforementioned lens member a small air space must be inserted. Thus, the inner member is composed of one part located in front of the plane of the pupil and one part located behind the plane of the pupil and it is thereby irrelevant whether the pupil lies in the glass medium or in the air.

In such a sequence of lenses, it is possible, at an aperture ratio of about 1:8, to attain an image angle of 120 and more if according to the invention, in that part of the positive lens member which adjoins the single meniscus, at least two cemented surfaces are inserted and are so designed that they turn their convex surfaces to ward each other and have a collective effect. This requirement is met if the refractive index on the convex side of the cemented surface which is nearer to the pupil, is smaller than on the concave side thereof and the refractive index on the concave side of the second cemented surface is likewise smaller than on the concave side thereof. Investigations have shown that by means of this step a satisfactory correction of the comatic aberrations can be attained for all light beams which are obliquely incident within the claimed image angle. It is advantageous to have the cemented surface which lies nearer to the pupil curved stronger than the cemented surface which is at a greater distance from it.

If such an objective is used for a projection with variable enlargement, or if measurements in a certain range of depth of a projected image are carried out, for example in the use of photogrammetric plotting apparatus, it is necessary, primarily in view of freedom from distortion in all magnification ranges, to have an image free from aberration of the primary principal point to the secondary principal point, while meeting the sinus-condition over the entire angular aperture corresponding to the image angle. It has been found that the conditions are met, particularly if the quotient between the numerical sum of the radii of curvature of the convex outer surfaces of the positive inner member, on the one hand and the distance between these surfaces on the other hand, is larger than 1.3 and smaller than 4. Tests have shown that if the limits are larger than 1.3 and smaller than 4, the best corrections for image defects can be obtained at this extremely larger image angle of 120. The focal length of the diverging single meniscus which is vicinal to the inner part, provided with the above described cemented surfaces, is in the range between --0.6 F and -1.4 F, F being the total focal length of the objective. If the image of the primary principal point to the secondary principal point is supposed to be achromatized also for a larger 3,320,015 Patented May 16, 1967 spectral region, the designing of the diverging single meniscus as a cemented member is indispensable in such manner that the positive lens consists of heavy flint glass and the negative lens consists of a glass which has as little color dispersion as possible. It is within the scope of the present invention to insert furthercemented surfaces into the lens members in order to further reduce specific aberrations.

FIGS. 1, 2 and 3 each represents sectional views showing the form and arrangement of the objective lenses according to the present invention depicting the notations employed in the numerical Examples 1, 2 and 3.

In the following, three working examples, in which the focal lengths amount to F: 100, are given. The individual lenses are denoted L. The individual lens members are denoted A to D. Lens member B consists of the two parts I and II which are separated by the pupil P. The image angle amounts to about at an aperture ratio of 1:8.

Example 1 Example 1 consists of the individual lenses L to L L is an uncemented diverging meniscus. L to L, are cemented together to form lens member I. Lens member II consists of the two cemented lenses L and L,,. Lenses L and L; are centering menisci which turn their concave side to the pupil. In lens member B the radii r, and r represent the collective cementing surfaces, which turn their convex surfaces to each other. The surface r, is provided nearer to the diaphragm bordering on air space I, with a curvature of 22.78, i.e. it is stronger curved than the surface r which is at a greater distance and has a curvature of 40.75. The quotient from the numerical sum of r, and r =139.7 and of the distance from r, to r,=80.26=0.803 F amounts to 1.74. The focal length of the single meniscus A is --l.02 F.

Example 2 In a magnification objective, the cementing surfaces in lens member B denoted by radii r, and r turn their convex surfaces to each other. The surface r, which is nearer to the pupil indicated by the cut, has a curvature corresponding to 24.06, and is stronger curved than the surface r with a curvature of 36.5, which is at a greater distance. The quotient from the numerical sum of r and r =l44.74 and of the distance from r, to r =78.93=0.789 F, amounts to 1.83. The focal length of the single meniscus A is -l.05 F.

Example 3 This is an objective for photogrammetric plotting in which the image of the primary principal point to the secondary principal point is practically free up to an aperture angle of :60" from spherical aberration if the sinus condition is observed. This correction extends still further over a larger spectral region. This objective is preferably used for an eightfold magnification and, thereby, the longer conjugate is on the side of the cemented single meniscus.

In lens member B all collecting surfaces r and r, turn their convex surfaces toward each other. The surface r, which lies nearer to the diaphragm with a curvature of 24.43, is stronger curved than the surface r which is at a greater distance and has a curvature of 37.65. The quotient from the numerical sum of r and r =141.71 and of the distance from r, to r,=141.71 and of the distance r, to r =77.5=0.775 F, amounts to 1.83. The focal strength of the single meniscus A is 1.055 F.

The radii of curvature of the lens surfaces are denoted herein r;

The thicknesses of the lenses are denoted d;

The air spaces are denoted l;

The refraction numbers for the helium line are denoted n The Abb numbers are denoted y.

What is claimed is:

1. A wide-angle objective comprising a compound converging component having two parts one of which is disposed on one side of the diaphragm plane of the objective and the other of which is disposed on the other side of such plane, and three diverging components, the converg- EXAMPLE 1 ing component being disposedbetween one of the divergmg components and the remaining two d1verg1ng compo- Kinds glass nents, each of the three diverging components being con- L men sci Th ckness or cave towards the converging component, and one of the ens space M two parts of the converging component that is between said one of the three diverging components and the diaphragm plane containing two cemented surfaces which Ll r 96 1='- M9651 are collecting and are convex towards each other, each of the two cemented surfaces having a converging effect H d 31 63 1 W52 36 6 and these two effects being additive and the other of the two parts having a converging effect, their indices of refraction n and their Abb numbers 1' have numerical 131317 values substantially as given in the following table, where- 11:0 30 2O 1n the symbols designate the following:

=-24s0.a L5 115:4.39 1.71070 20.7 L the mlvldual lenses I! =+101.0 r the radn of curvature of the individual surfaces, L5 n d the axial thicknesses of the lenses,

1i=29.01 l the air spaces between lenses, L7 (11:40.5 M8744 7M n the refractive indices for the helium d-line, and

r"=-54.57 l 13 64 v the Abbe number.

4 The suffices denote the particular item in sequence from 3 7. L8 6 3 1 48m 0 0 the ob ect side or front of the ob ective.

30 EXAMPLE 2 Kinds of glass Radius 0! Thickness or Lens curvature air space Kinds of glass a v Radius of Thickness or Lens curvature air space 1.1 di=25a1 1. 69651 55.0

n =+a7.0e n =+00.20 1i-=34.17 L1 di=10.25 1. 72825 28.3 n =+e0.s5

n =+2n1e1 L2 (11:31.03 1. 72052 36.6 L2 d|=4.0t 1.69680 65.6 n =-40.75

n =+3c.01 L3 (11:11.11 1.69823 31.1

1i=a5.05 n =+22.7s n +7280 L4 d4=6.83 1. 71317 36. 5

d==32.l0 1. 7335 51.0 n =+2s42.4 rs =36.50 h=0.30

d|=3.20 1. 7040 as. 7 r1 -24s0.3 n =+24.06 d$=4.39 1. 71079 29. 7

d|=43.63 1. 7149 r. =+1o1.0 r7 =-71.ss d1=2s.0 1. 71079 53.9

h=30.0 n =69.85 n =-3e.5a 11=29.01 L6 dfl=4-01 1.48740 70.0

n -54.54 L7 d1=4.05 1. 48744 70. 0

l1=13.63 I1i=-54.57 m=-42.85 l4=13.64 1,1 d1=8.3 1.48749 70.0 m=43.96

n|=-70.39 L8 d =6.33 1.48744 70.0

EXAMPLE 3 0 2. A wide-angle ob ective comprismg a compound conadl f Tm k Kinds of glass verging component having two parts one of which is dis- R 0 c '5 posed on one side of the diaphragm plane of the objective t airs a e d Lens me p c m and the other of Wind) is disposed on the other s1de of such plane, and three diverging components, the converg- =+00.0a ing component being disposed between one of the diverg- Ll n +213 63 1-72825 ing components and the remaining two diverging com- L2 di=3.82 1.69680 55.6 ponents, each of the three diverging components being 11:36 24 concave towards the converging component, and one of n =+70.65 the two arts of the conver ing com onent that is beit a139 172916 54 8 P g p L3 tween sald one of the three diverging components and L4 43 d1=4.87 6 the diaphragm plane containing two cemented surfaces L5 H1300 65 which are collecting and are convex towards each other, 11:0 30 each of the two cemented surfaces having a converging =-254a.2 36 effect and these two effects being additive and the other L6 of the two parts having a converging effect, their indices r 3G 93 l;=30.26 of refraction n and their Abb numbers 1 having numeri- L7 w- 1;=4.07 1.4375 70.0 cal values substantially as given in the following table,

14:13 73 wherein the symbols designate the following: g m= 43'62 d =g 33 14375 70 0 L the individual 1611868,

m=-71.08 r the radn of curvature of the 1nd1v1dual surfaces,

I the air spaces between lenses, n the refractive indices for the helium d-line, and y the Abb number.

The suffices denote the particular item in sequence from the object side or front of the objective.

Kinds of glass Radius of Thickness or Lens curvature air space fld v n +9626 L1 (l1=19.25 1.72825 28. 3

rz =+216.61 L2 dz =4.01 1 69680 55. 6

li=35.95 n +7286 L3 d1=32.10 1.7335 51.0

1'0 =+24D6 L5 d5=43.63 1.7149 41.3

l:=300 rs 36.58 L6 du=4.01 1. 43749 70. 0

is=13.63 1'1u= 42.85 L7 d1=8.3 11 487-19 70. 0

3. A wide-angle objective comprising a compound converging component having two parts one of which is disposed on one side of the diaphragm plane of the objective and the other of which is disposed on the other side of such plane, and three diverging components, the converging component being disposed between one of the diverging components and the remaining two diverging components, each of the three diverging components being concave towards the converging component, and one of the two parts of the converging component that is between said one of the three diverging components and the diaphr-agm plane containing two cemented surfaces which are collecting and are convex towards each other, each of the two cemented surfaces having a converging eflFect and these two effects being additive and the other of the two parts having a converging effect, their indices of refraction n and their Abb numbers I having numerical values substantially as given in the following table, wherein the symbols designate the following:

6 L the individual lenses, r the radii of curvature of the individual surfaces, d the axial thicknesses of the lenses, 1 the air spaces between lenses, n the refractive indices for the helium d-line, and v the Abb number.

The suffices denote the particular item in sequence from the object side or front of the objective.

Kinds of glass Radius of Thickness or Lens curvature air space n +9903 L1 d1 =2! .36 1. 72825 28. 3

r2 +213.63 L2 (ll =3.82 1. 69680 55. 6

11:36.24 rt =+70.65 L3 d1=31.39 1. 72916 54. 8

n =+24.43 L5 ds=6.10 1. 71300 53. 0

i|=0.30 r; 2543.2 L6 ds=34.84 1. 7102 36. 5

n 7l.0fl

l =30.26 rm= '36.93 L7 d1=4.07 1.4875 70.0

l4=l3.73 ril= -43.fi2 L8 di=9.33 1. 4875 70. 0

References Cited by the Examiner UNITED STATES PATENTS 2,721,499 10/ 1955 Bertele 8857 3,039,361 6/1962 Baker 8857 3,154,628 10/1964 Bertele 8857 FOREIGN PATENTS 575,975 5/1959 Canada.

JEWELL H. PEDERSEN, Primary Examiner.

DAVID H. RUBIN, R. I. STERN, Assistant Examiners. 

1. A WIDE-ANGLE OBJECTIVE COMPRISING A COMPOUND CONVERGING COMPONENT HAVING TWO PARTS ONE OF WHICH IS DISPOSED ON ONE SIDE OF THE DIAPHRAGM PLANE OF THE OBJECTIVE AND THE OTHER OF WHICH IS DISPOSED ON THE OTHER SIDE OF SUCH PLANE, AND THREE DIVERGING COMPONENTS, THE COVERGING COMPONENT BEING DISPOSED BETWEEN ONE OF THE DIVERGING COMPONENTS AND THE REMAINING TWO DIVERGING COMPONENTS, EACH OF THE THREE DIVERGING COMPONENTS BEING CONCAVE TOWARDS THE CONVERGING COMPONENT, AND ONE OF THE TWO PARTS OF THE COVERGING COMPONENT THAT IS BETWEEN SAID ONE OF THE THREE DIVERGING COMPONENTS AND THE DIAPHRAGM PLANE CONTAINING TWO CEMENTED SURFACES WHICH ARE COLLECTING AND ARE CONVEX TOWARDS EACH OTHER, EACH OF THE TWO CEMENTED SURFACES HAVING A CONVERGING EFFECT AND THESE TWO EFFECTS BEING ADDITIVE AND THE OTHER OF THE TWO PARTS HAVING A CONVERGING EFFECT, THEIR INDICES OF REFRACTION ND AND THEIR ABBE NUMBERS V HAVE NUMERICAL VALUES SUBSTANTIALLY AS GIVEN IN THE FOLLOWING TABLE, WHEREIN THE SYMBOLS DESIGNATE THE FOLLOWING: L THE INDIVIDUAL LENSES, R THE RADII OF CURVATURE OF THE INDIVIDUAL SURFACES, D THE AXIAL THICKNESS OF THE LENSES, L THE AIR SPACE BETWEEN LENSES, ND THE REFRACTIVE INDICES FOR THE HELIUM D-LINE, AND V THE ABBE NUMBER. THE SUFFICES DENOTE THE PARTICULAR ITEM IN SEQUENCE FROM THE OBJECT SIDE OR FRONT OF THE OBJECTIVE. 